Design of a CMOS 65‐nm inductor‐less VCO for ISM applications in the VHF band

Abstract

Summary This paper presents a design of a CMOS cross‐coupled voltage‐controlled oscillator (VCO) using active inductors (AIs) for wide‐band applications and can also be applied to various wireless technologies standards. The compatibility of this design to different wireless standards highlights its potential to be implemented at the core of the communication front end in the Internet of Things (IoT). The proposed AI design employs a gyrator‐C topology as the basic structure to generate an inductance. The VCO uses a cross‐coupled oscillator structure with a pair of varactors to sweep the frequency. Two extra capacitors, between the AIs and the outputs of the VCO core tank, are employed to enhance the performance of the phase noise and make the VCO work similarly to a linear transconductance (LiT) oscillator. Both the AIs and the VCO are designed in the TSMC 65‐nm CMOS technology, and the performance is analyzed using postsimulation results, as well as through measurements. The fundamental frequency spans from 140 to 463 MHz. Thus, the relative tuning range of this design is approximately 107%. The optimal phase noise of the design is around −97 dBc/Hz at 1‐MHz offset. Furthermore, it achieves an excellent figure of merit (FOM) around −163 dBc/Hz with a direct current (DC) power consumption less than 3 mW. The proposed design shows an advantage in phase noise and power consumption in comparison with previous active inductor VCO and ring VCO designs, respectively. The final layout occupies only 0.4 × 0.62 mm2 including the pads. The proposed AI‐VCO shows a compact size, linear tuning, low power consumption, and good phase noise performance.

A 0.3–5 GHz, low‐power, area‐efficient, high dynamic range variable gain low‐noise amplifier based on tunable active floating inductor technique

“…Several techniques have been proposed in the literature describing active inductors instead of passive spiral inductors for different applications such as voltage-controlled oscillators, tunable filters, and LNAs. [22][23][24][25][26] Existing approaches to design active inductor circuits are generally divided to grounded and floating techniques. [22][23][24][25][26] In Branchi et al, 22 a high-quality factor floating active inductor, suitable for RF and microwave applications, based on two cascaded pairs of highly linear capacitance gyrators, which provide a symmetric and reciprocal structure, is proposed.…”

“…[22][23][24][25][26] Existing approaches to design active inductor circuits are generally divided to grounded and floating techniques. [22][23][24][25][26] In Branchi et al, 22 a high-quality factor floating active inductor, suitable for RF and microwave applications, based on two cascaded pairs of highly linear capacitance gyrators, which provide a symmetric and reciprocal structure, is proposed. In Minaei et al, 27 a gyrator approach is used to design a floating active inductor in the range of 6 to 284 nH.…”

Novel six‐phase ring voltage controlled oscillator with wide frequency tuning range

“…In some of VCOs, active inductors are employed instead of passive samples for different applications. 11 In addition, the ring VCOs typically have wide frequency tuning range while the LC VCOs generally have narrow frequency range. Another advantage of the ring VCOs is their ability to generate multiple phases.…”

“…The large area of LC VCOs arises due to using of passive spiral inductors in their resonators. In some of VCOs, active inductors are employed instead of passive samples for different applications 11 . In addition, the ring VCOs typically have wide frequency tuning range while the LC VCOs generally have narrow frequency range.…”